Prof Michael KimlinUVA radiation is more responsible for this photo-ageing - that is wrinkling, premature sagging of the skin - where UVB, we are very sure that it actually causes things like sunburn, skin cancers and risk of other skin-related disorders.

Ruben MeermanSo, what affect has all that UV had on MY skin?

Prof Michael KimlinWhat this machine allows us to do is look at excessive pigmentation as a by-product of sun exposure. So the body's defence mechanism when we have exposure to sunlight is to produce pigment. Well, here's your standard photograph that we took. This is showing what's happening on the surface of your skin. Now we're going to have a look underneath your skin. OK.

Ruben Meerman(Gasps) Oh, my goodness.

Prof Michael KimlinSo the thing that I see first off is these pigmentation points all through your face, but evenly distributed from your forehead down to your chin. It shows me that this is actually chronic sun-exposure, lifetime sun-exposure. The other thing is looking at what we call 'photo-ageing' - premature ageing due to sun-exposure - and the classic point that I can show you here is actually these wrinkles that I can see on your forehead, also around your eyes and even started in the corner of your mouth.

NARRATIONProfessor Kimlin ran this same test on a large sample of volunteers.

Prof Michael KimlinThe key thing that we found was that exposure at very low levels and at early life is actually quite important for imprinting this damage that we see in our skin. So our targeted health campaigns on protecting young people's skin is actually more important than ever.

NARRATIONSunscreens are a major part of the campaign to protect our skin, and they fall into two main classes - those lotions based on organic UV filters and those containing metal oxides.

Associate Prof Paul WrightThis second class block out the full range of ultraviolet A and B damaging rays, so it's much more advisable to be using a sunscreen that has the metal oxides.

NARRATIONIn this lab at RMIT University, skin cells are exposed to a dose of ultraviolet light, both on their own and with the addition of extremely small particles of metal oxides called 'nanoparticles'. So here are the results. What did you find?

Associate Prof Paul WrightWell, as you can see in the first panel here, this is what normal human skin cells look like in culture, and they're flat and spread out. But if you expose them to ultraviolet light - here on the right side - a day later, you can see that many of them are lifted off and died and the rest have rounded up. So this is enough UV dose - similar to that from the sun - that can cause skin cell damage. So you really need to protect against that.

Ruben MeermanRight.

Associate Prof Paul WrightThis time, we added the nanoparticles, and, as you can see, there's a lot of live cells there - they're much like the normal cells. So the nanoparticles have been protective.

NARRATIONSome people have concerns that the nanoparticles in the sunscreen could be a health risk.

Prof Brian GulsonWe were trying to determine whether or not the nanoparticles that are in the sunscreen penetrate the skin and then finish up in blood and urine or get into the body.

NARRATIONThe researchers took 20 volunteers to the beach and applied sunscreen to their backs twice a day for five days.

Prof Brian GulsonWhat we found was that small amounts of zinc from the zinc oxide in the sunscreens got through the skin and finished up in the blood and urine. The important thing is, though, that the amounts were really quite tiny. They were about a thousandth of the amount of zinc that's floating around in our body.

NARRATIONOne surprising result was that the zinc levels in the blood continued to increase after they stopped applying the sunscreen.

Prof Brian GulsonSo that was out to 11 days, and we only applied the sunscreen for five days. So, what we need to do now is do a longer-term study, probably over three weeks, with titanium dioxide, and with some people with compromised skin - maybe eczema or something like that.

NARRATIONSo, what happens to the nanoparticles that DO make it through the skin?

Associate Prof Paul WrightThe immune system is responsible for getting those sort of particles out of your body, so what we did is take human immune cells, exposed them to nanoparticles, and we went to the Australian Synchrotron to see if we could visualise these nanoparticles inside the human immune cell. So that's what this picture shows on the left. And you can see that the nanoparticles are there with the human immune cell. We then used electron microscopy, and this picture on the right shows that after a couple of layers have been taken off the immune cell, the little black dots inside the cell are intact nanoparticles. So the human immune cells are doing the job that they're supposed to do. They can clear any nanoparticles like this that could get through and perform their normal function.

NARRATIONResearch into sunscreens is ongoing, but what is beyond doubt is the high risk of skin cancer and the damage that can result from exposure to ultraviolet light.

Prof Michael KimlinLook, to be honest, the best way to protect your skin is through sun-avoidance. That is truly the best way to protect your skin. But unfortunately, we live in such a beautiful climate in Australia, we can't spend all day indoors, so I think we should start thinking about a combination of protection strategies - so looking at sun-avoidance combined with sun-protection with clothing, and also sunscreen as a last line of defence.

Ruben MeermanSo the message is clear and you've heard it before - if you want to protect your skin from damage, don't expose it to too much sun.

YOUR COMMENTS

Comments for this story are closed. No new comments can be added.

Peter - 31 Oct 2012 10:03:22am

There has been research (published in the British Journal of Dermatology) which shows doctors are reporting a diagnosis of a stage 1 melanoma skin cancer even when the patient has only a non-cancerous lesion, classified after surgery. These diagnoses appear to be skewing the disease rate significantly. In addition to this miss-diagnosis and a growing body of evidence which shows sun exposure is not the primary cause of melanoma, the study noted the location and distribution of the lesions did not correspond to the typical sites of lesions caused by sun exposure.

Chuds - 20 Sep 2012 6:17:26pm

Where can regional Australians with sun damaged skin access a thorough, specialised annual skin check for health rather than cosmetic reasons? My GP just peers and pokes at suspects then cuts them out.Skin checks are potentially as important as cholesterol, blood sugar and BP checks when you've lived most of your life in the sun.

Muzza - 19 Sep 2012 10:09:00pm

It was interesting to view your program on laser therapy, however the program did not go into the use of lasers for broken capillaries. I personally have had several different laser therapies from different doctors. All promising great results to remove the capillaries but none delivering. One laser treatment last year left me very bruised and blistered. Are there any laser treatments available that will remove broken capillaries?The only thing these treatments have done for me is to cause embarrassment and the loss of $3,500.

Dr Neil Burry - 18 Sep 2012 11:00:38am

I have posted a comment which has apparently gone unnoticed or has been ignored.Nothing makes sense in biology except in the light of natural selection.So wrote Theodosius Dobzhansky in the American Biology Teacher in March 1973. Those chosen by natural selection for the Australian environment were black. How many malignant melanomas in one year among white Australians? Biologists should not ignore the politics of their science!The Australian public should not be denied awareness of this essential biological tenetNeil Burry

Dr Neil Burry - 15 Sep 2012 12:32:56pm

White skinned people were chosen by natural selection for countries where sun exposure islimited.Biology is nothing without natural selection.Natural selection should have been an integral part of the program.Telling Australians that genuine Australians have black skins may be distasteful? for the presenters of Catalyst but is surely the essence of biology.In an explanation of why it is essential to stay out of the sun let us know the incidence of malignant melanoma.I understand that 10,000 are diagnosed every year. Let us know the statistics.Biological politics!

Brian - 02 Oct 2012 4:24:51pm

Black skinned people can also get skin cancer (albeit with much less occurrence). As a 'Dr' you should know this....